Is it possible to be able to hold the spacebar to make a player jump higher? Game Engine
Yes, it is possible.

Typically you measure the time between pressed and released. Minimum is one frame, so you will always been able to measure the time.

You need to define how you want to convert the time to jump height (or force or velocity or whatever.



Due to it's dynamic nature I suggest to implement the usage of the result that in Python.